( PR4US.com | Press Release | 2020-10-29 11:28:37 )
Without vacuum, it would also be impossible to handle and transport cartons or automate palletizing and order picking systems. Various filling machines also use vacuum to feed in the product or handle packaging (pick & place).
1. Understanding the physics of vacuum
The main purpose of vacuum pumps is to suck air out of a closed system in order to generate vacuum. The level of vacuum used depends on the application, but always ranges from between 1 and 900 millibars [mbar] (absolute). In addition to the vacuum level achieved by a vacuum pump, a vacuum pump’s pumping speed is another key variable. The pumping speed indicates how much air a vacuum pump is able to extract within a certain period of time. Both technical parameters are related to one another. This relationship is depicted in the so-called pumping speed curve.
2. Choosing the ideal vacuum generator
There is an array of different types of vacuum technology. The following mechanical vacuum pumps or blowers are mainly used in the field of packaging technology:
1. Dry-running rotary vane vacuum pumps
Dry-running rotary vane vacuum pumps are ideal for a variety of packaging processes. These pumps are able to reach a maximum vacuum level of 100 mbar. However, the pumping speed should not exceed 40 m3/h as the vanes in larger vacuum pumps of this type wear more and thus result in excessive increases in maintenance effort and the related costs.
2. Oil-lubricated rotary vane vacuum pumps
Oil-lubricated rotary vane vacuum pumps achieve a vacuum level of 0.1 mbar. They are the standard in vacuum packaging but may also be used in many other applications throughout industry. Rotary vane vacuum pumps are able to cover pumping speeds from 3 to 1,600 m3/h. The operating fluid oil is transported in an internal circuit.
3. Dry claw vacuum pumps
Dry claw vacuum pumps do not require any operating fluids in the compression chamber. They have a contact-free operating principle and are therefore nearly maintenance-free. They achieve ultimate pressures of up to 40 mbar and can be regulated from 20 to 80 Hertz rotational speed, which makes them suitable for processes in which changing output requirements should be met on a demand-driven basis. Common pumping speeds are between 40 and 1,000 m3/h.
4. Dry screw vacuum pumps
Dry screw vacuum pumps also do not require operating fluids to compress the extracted air. They achieve a vacuum level of 0.1 mbar and below. Since most applications operate at much higher pressures, screw vacuum pumps are generally only used in larger vacuum packaging machines as an alternative to a rotary vane vacuum pump with an additional vacuum booster.
5. Side channel blowers
One of the distinguishing features of side channel blowers is their high pumping speed. Because they only achieve low differential pressures, they are only able to achieve a maximum vacuum level of 500 mbar. They are therefore ideally suited to applications that require a high pumping speed in combination with a low vacuum level. While side channel blowers are maintenance-free, they are less energy-efficient if they are used close to their performance limits.
2. Dimensioning the vacuum supply
It is important for users to exactly understand their particular process and to know which vacuum level and pumping speed are required for it. Uncertainty often leads to choosing a vacuum pump with excessive dimensions, resulting in unnecessary energy and operating costs. In scenarios with changing process parameters, we recommend vacuum pumps that can be controlled on a demand-driven basis and that either constantly maintain the required vacuum level or guarantee a consistent pumping speed. We always recommend consulting a vacuum specialist.
3. Choosing between a central or local vacuum supply
The decision between a central vacuum supply for an entire plant or multiple vacuum consumers, and a decentralized vacuum supply where each individual machine has its own vacuum pump, can have a decisive impact on your procurement and operating costs. It is therefore important to carefully weigh your options.
Individual vacuum pumps that are installed inside a machine or in close proximity to it are cheaper than a central vacuum supply, not least because you no longer have to cover the costs for procuring and installing a pipeline system. However, it is important to remember that a central vacuum supply uses far fewer vacuum pumps than a decentralized solution. Operating costs are reduced because your maintenance and energy costs are lower. What is more, a central vacuum supply can be set up outside of packaging or production areas. This means that no noise or heat builds up at your work stations.
4. Increasing efficiency with vacuum vessels or buffers
Vacuum vessels on individual vacuum pumps and even on larger vacuum supply systems can save huge amounts of energy.
They can be installed between the vacuum pump or vacuum system and the consumers. Using a simple control mechanism, the vacuum in the vessel can be maintained at a particular level. Once this level has been reached, the vacuum pump switches off automatically or switches to idle mode. If the pressure in the vessel rises above a defined value, the vacuum pump switches back on.
5. Working with vacuum experts
Every form of vacuum technology and every vacuum system configuration has its advantages and disadvantages. Picking the best vacuum solution calls for in-depth knowledge of vacuum technology as well as an understanding of the user’s processes.
That is why we always recommend working with a vacuum specialist.
6. Thinking about energy costs
A vacuum generator’s energy costs cannot be calculated on the basis of the nominal motor rating because this only provides a limited reflection of the actual power consumed. Information regarding the nominal motor rating and the additional specification of a service factor confuse the matter.
Energy consumption can only be compared directly if you know the shaft power across the entire pressure profile and if you know the pressure conditions during the packaging process. Reputable manufacturers of vacuum pumps and systems are able to calculate anticipated energy consumption for their customers.
7. Calculating total costs
When purchasing vacuum technology, you should do more than just compare the investment and energy costs of different vacuum pumps and different manufacturers to help you make your decision. You should always look at the anticipated total costs over an extended period. Like energy costs, operating costs can also vary greatly. It is important to consider maintenance work and the resulting downtime, costs for spare parts, and the procurement and disposal of operating fluids.
8. Looking to the future: Industry 4.0
Today’s vacuum pumps allow for easy maintenance with easy access to all service relevant parts. Busch also offers contractual services at a fixed rate and takes responsibility for the operational safety of its vacuum pumps and vacuum systems. The operator is thus protected and does not need to have its own team of service technicians. Busch has now vacuum pumps in its product portfolio that feature intelligent sensors to inform the operator or service technician about pending maintenance work in real time. What is more, also retrofit kits are on offer that can be used to make existing vacuum pumps ready for Industry 4.0.